Mrs. Etsell
CHAPTER 5K SCIENCE STUDY GUIDE
THE PERIODIC TABLE
“Periodic” means repeated in a pattern.
Periodic Table – the arrangement of the elements according to repeated changes in
properties. It was designed by Dimitri Mendeleev.
Dimitri Mendeleev first arranged the elements in the periodic table according to how
they act and by increasing atomic mass
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British scientist, Henry Mosely, corrected Mendeleev’s arrangement by ordering the
elements according to increasing atomic number.
Periodic Law – states that the chemical and physical properties of elements are periodic
functions of their atomic numbers.
Groups are the vertical columns
Periods are the horizontal rows
Group 1 contains H, Li, Na, Rb, Cs,. Fr, Pb – all these elements act alike BECAUSE they
all have the same number of electrons (1) in their outer level
H
Li
Na
K
Their are 18 groups in the Periodic Table. Each group’s elements have the same number
of electrons in their outer level.
So…….All elements in group 1, have 1 electron in their outer level
All elements in group 2, have 2 electrons in their outer level
All elements in group 3, have 3 electrons in their outer level
Elements are CLASSIFIED as either metals, nonmetals, or metalloids.
METALS:
 Are malleable (can be flattened by hammering)
 Are good conductors of thermal energy
 Are ductile (can be drawn through thin wires)
 Tend to be shiny
 Most have few electrons in their outer level
 Most are solids at room temperature
 Mercury, however, is a metal that is a liquid at room temperature
NONMETALS
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Found to the right of the zigzag line
Their outer levels are almost full
Nonmetals called Nobel Gases have a completely filled outer level of electrons.
Nonmetals are not malleable or ductile and are poor conductors of thermal
energy.
METALLOIDS
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Also called semiconductors
They are found on/around the zigzag line
Most have a half-filled outer level of electrons
Some metalloids are like metals and some are like nonmetals
CHEMICAL SYMBOLS
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Each element has a chemical symbol
Names of elements often come from the scientist that discovered them.
Others are names according to the places they were studied or found in
Example:
Sulfur (name)
S (symbol)
Calcium (name)
Ca (symbol)
PERIODS
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The horizontal rows of elements on the periodic table
The elements in a row become less metallic from left to right
Elements at the left are very metallic
Elements further right are less metallic
Elements at the far right on a row are nonmetals
GROUPS
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The vertical columns of elements on the periodic table
Elements in the same group have similar chemical and physical properties
Groups are also called families
GROUP NUMBER – tells how many electrons are on the outer level
PERIOD NUMBER – tells which level is the outer level
Example:
Potassium (K) is in group 1, period 4.
That means it has 1 electron on its outer level, based on its group
number and its outer level is level 4, based on its period number.
Calcium is in group 2, period 4
That means it has 2 outer level electrons on level 4.
GROUPING ELEMENTS
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The most reactive elements are in groups 1 and 2
These elements have 1 or 2 electrons in their outer levels
They only have to give up 1 or 2 electrons to have a filled outer lever and
therefore, are very reactive
GROUP 1 – Alkali Metals
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Have 1 electron in their outer level
Are very reactive
Are soft enough to be cut with a knife, silver-colored, shiny, have a low density
GROUP 2 – Alkaline-earth Metals
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Have 2 electrons in their outer level
Are very reactive, but less reactive than the alkali metals in group 1
This is because it is more difficult to give up 2 electrons that 1 electron
GROUPS 3-12: TRANSITION METALS
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Contains metals
Have 1 or 2 electrons in their outer levels
Are less reactive than the alkaline-earth metals in group 2
Transition elements do not give away electrons as easily as those in groups 1
and 2
Titanium is a transition element used to make artificial hips and is not very
reactive
Iron is also a transition element, but is very reactive
GROUPS 13-16
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- GROUPS WITH METALLOIDS
Group 13 - the Boron Group – has 3 outer level electrons
Group 14 - the carbon Group has 4 outer level electrons (diamonds are a
natural form of an element in the carbon group)
Group 15 - the Nitrogen Group has 5 outer level electrons
Group 16 - the Oxygen Group has 6 outer level electrons
GROUPS 17 AND 18:
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Nonmetals Only
GROUP 17 - the Halogens.
They have 7electrons in their outer level
are the most reactive nonmetals (only need 1 electron for a full level)
They are poor conductors of electricity
Fluorine, Chlorine, Bromine, Iodine and Astatine are group 17 halogens.
Note* When group 1 elements combine with gropu 17 – they form a salt
compound – EX. Lithium bromide, Sodium fluoride, Potassium chloride. Etc.)
GROUP 18 – THE NOBEL GASES
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These are unreactive nonmetals
Their outer energy levels are full and they don’t need to gain or lose
electrons
Helium, Neon, Argon, Krypton, Xenon, and Ununoctium are Nobel Gases
Argon is the most abundant noble gas in our atmosphere.
USES OF NOBEL GASES:
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Light bulbs filled with argon last longer
Neon used in “neon lights” produce an orange-red color
HYDROGEN
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Its properties are unlike the properties of any other group of elements.
It has 1 electron on its outer level
It is reactive
It is a colorless, odorless gas at room temperature
Reacts explosively with oxygen
It is used as a fuel in rockets
Its properties are more like nonmetals than metals
Hydrogen is the most abundant element in the universe
LANTHANIDES
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Transition metals from
Period 6 that are placed at the bottom of the periodic table.
They are shiny and reactive
Some of these elements are used to make steel
ACTINIDES
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Transition elements from Period 7 that are placed at the bottom of the periodic
table.
All actinide atoms are unstable and radioactive
Americium, element 95, is used in smoke detectors
Both Lanthanides and Actinides are placed at the bottom of the periodic table to keep the
table from being too wide
AIR
Breath in
Breath out
Nitrogen
80%
Nitrogen
80%
Oxygen
18%
Oxygen
13%
Argon
1%
Carbon Dioxide
5%
Mix
1%
Argon
1%
Mix
1%